In nutrition, medicine, and animal science, metabolism research is often focused on solving questions using a single organism. Outcomes are most often linked to translational outcomes, understanding or treating a disease, optimizing nutritional status, improving select qualities of production animals, which have tremendous value to human and animal health as well as economic benefit. There is also value in clarifying basic biological principles and integrative systems that determine how organisms function and deal with their environment. Relevant to both translational and basic research questions, comparative metabolic physiology provides a context by which new "omics" technologies and other approaches can be coupled to multi-species metabolic phenotype diversity. These principles were highlighted at the "Adipose and Lipid Biology: Crossing Taxonomic Boundaries" symposium held at the 2013 Experimental Biology meeting in Boston, MA. By considering differences and shared physiology across a spectrum of phenotypes (especially when considering "extremes" that have emerged from evolutionary processes or breeding selection), one may unmask subtle processes and learn from natural adaptations.